Music has existed in many societies and in many forms for millennia. Music has been called an emotional language and provides a societal connection that goes beyond mere prose or unaccompanied poetry. There are many societal connections with music. For instance, music can be used to express feelings of pride or nationalism, such as when a country's national anthem is played; or it can be used to express solidarity with a sports team, such as when an alma mater is played during a college football game; or music can be used to express emotions of joy and excitement, such as when a bride walks down the aisle accompanied by music during a wedding ceremony. Music can also be an important component in learning and childhood development. Many elementary schools include music programs, and the benefits of music education for children are well documented. In addition, experimenting with music is an enjoyable activity. Music is defined and characterized by tones, pitches, and durations. Tones, or notes, are associated with a musical pitch, or frequency. The duration of a note specifies the length of time that a note is sounded. Furthermore, a specific note quality, or timbre, can be associated with each note. It is common for timbre of digital music to correspond to a live instrument, such as a piano, trumpet, or saxophone. The various components of a musical note can be called its attributes.
The musical attributes of a piece of music can be communicated in several ways. One common way to express musical notation is to use staff nomenclature where notes are represented as marks on a series of lines which represent one or more octaves of a musical scale. Such representations are often called sheet music. Sheet music that represents musical expression for instruments in the context of a band or orchestra is often called a musical score. A sheet music score can be used to represent complex musical arrangements played by over hundreds of instruments in a large orchestra. The instruments each contribute to the melody, harmony, and rhythm of a musical piece according to the dictates of the composer or arranger. Of course, technology can be used to allow for digital representation of music. There are many forms of digital representation of music, such as the .wav format used on digital optical discs. Another common format is the .mp3 format used for compressed digital storage and transmission. Musical scores can be captured in a musical instrument digital interface file, or .midi or .mid, format.
Digital music can, of course, be played back. That is, it can be converted from digital ones and zeros in a file format into an audio tone played through a loudspeaker, headphones, or earbuds. Various attributes of the playback can be controlled. These attributes include volume, which corresponds to the amplitude of a resulting sound pressure wave, and equalization, which corresponds to the relative amplitude of various frequency ranges within the audio frequency range, such as a bass boost or a treble cut. Other attributes such as tempo and instrumental emphasis can be controlled during playback as well.